Wireless networks enable large numbers of users to take advantage of mobile telephony and data services. To this end, inter-network roaming has become a fairly standard feature that enables mobile users to receive wireless service on their wireless terminals as guests in networks that are not their “home” network across large geographic regions. To support inter-network roaming, the Customized Applications for Mobile network Enhanced Logic set of protocol standards (“CAMEL”) has been developed over the years to enable network operators to offer services such as no-prefix dialing in foreign countries and seamless multimedia messaging. CAMEL was originally defined by the European Telecommunications Standards Institute and more recently by the 3GPP group to operate with GSM, UMTS, and 3GPP-based wireless networks. See, e.g., 3GPP Technical Specification, 3rd Generation Partnership Project; Technical Specification group Core Network and Terminals; Customised Applications for Mobile network Enhanced Logic (CAMEL) Phase 4; Stage 2 (Release 9), 3GPP TS 23.078 V9.2.0 (2010-09), which is incorporated by reference herein. A well-known CAMEL-compliant protocol is the CAMEL Application Part (“CAP”) signaling protocol. CAP is used for signaling and communication among CAMEL-enabled entities within a wireless network.
A complete list of available and contemplated CAMEL-enabled supplementary services is beyond the scope of the present disclosure, but examples include:                barring calls or approving a call to continue,        monitoring a call for call connect and disconnect,        providing announcements or voice prompts to voice users,        controlling call duration,        enabling debits/charges to be applied against a pre-paid wireless calling plan, and providing the user with account balance announcements,        tracking whether the subscriber is reachable (i.e., in-network) or roaming outside the network,        controlling mobile-originated and mobile-terminated text messaging through both circuit-switched and packet-switched network entities, and        enabling the same access number for voice mail across different networks, etc.        
CAMEL-enabled entities within a wireless network include one or more service control function entities and the gateway mobile location center, as explained in more detail in regard to FIGS. 1 and 2 below.
In the context of mobile detection, surveillance, and tracking operations, CAMEL-enabled services in the prior art are not well suited for such applications. A mobile detection scenario is illustrated and described in reference to FIGS. 1 and 2 below, accompanied by a discussion of the disadvantages that it presents. FIG. 1 depicts a schematic diagram of a portion of wireless telecommunications network 100 that is available in the prior art. Wireless network 100 comprises: mobile switching center (“MSC”) 101, base station controller (“BSC”) 103, base station 105, serving mobile location center (“SMLC”) 107, gateway mobile location center (“GMLC”) 109, home location register (“HLR”) 111, service control function (“SCF”) entity 113, general packet radio service (“GPRS”) support node 115, and wireless telecommunications terminal 150. Wireless network 100 and its constituent elements are well known in the art.
Wireless network 100 as illustrated in FIG. 1 is a wireless network that is configured to operate according to the Global System for Mobile Communications (“GSM”) standards. The depicted terminology herein, including CAMEL-related terminology, is often GSM-specific for ease of understanding, and more general terms are used in some instances. In some configurations, wireless network 100 could be a Universal Mobile Telecommunications System (“UMTS”) network, or based on the 3rd generation Partnership Project (“3GPP”) family of standards, or a Code Division Multiple Access (“CDMA”) or CDMA-based network. It will be clear to those skilled in the art what the appropriate terms are for non-GSM networks and non-CAMEL protocols.
Mobile switching center (“MSC”) 101 is a wireless network element that, among other functions, provides mobility management and circuit switched call support along with connectivity to the Public Switched Telephone Network (“PSTN”). Mobile switching center 101 is CAMEL-enabled, meaning that it (non-exclusively) communicates CAMEL-compliant signaling to and from other elements of wireless network 100 as described in more detail below. In some CAMEL-enabled networks, a CAMEL-enabled mobile switching center 101 also collects information that is needed for pre-paid call accounting and charging. CAMEL-enabled mobile switching centers are well known in the art. For simplicity, distinctions between a serving mobile switching center and other mobile switching centers will be kept to a minimum herein as such distinctions are well known in the art.
Base station controller (“BSC”) 103 is responsible for signaling between a wireless terminal and the main switching elements of the network such as mobile switching center 101 and GPRS support node 115. Typically, base station controller 103 controls a plurality of base stations 105, but only one base station 105 is illustrated here for simplicity. Base station controller 103 is well known in the art.
Base station 105 is responsible for the wireless radio frequency (“RF”) communication link to the wireless terminals in the area. Base station 105 serves a cell of wireless network 100 and has a unique cell identification within the network. A group of cells define a “location area.” As illustrated in FIG. 1, base station 105 is the serving base station to wireless terminal 150, i.e., provides the necessary service that enables voice and/or data services to wireless terminal 150. Base station 105 is well known in the art.
Serving mobile location center (“SMLC”) 107 collects information from the wireless terminals that are in service with base station controller 103, e.g., wireless terminal 150, and estimates their respective locations with a certain level of precision or resolution, e.g., estimating a location with a radius of 300 meters. Serving mobile location center 107 is well known in the art.
Gateway mobile location center (“GMLC”) 109 is an element of the wireless network that typically interfaces with external location services systems that provide higher level applications. Within wireless network 100, gateway mobile location center 109 transmits location requests to mobile switching center 101 and/or GPRS support node 115 and receives location estimates that were generated by serving mobile location center 107 and transmitted therefrom “upstream” to gateway mobile location center 109. Gateway mobile location center 109 is well known in the art.
Home location register (“HLR”) 111 is a centralized element of wireless network 100 that stores subscriber profiles associated with wireless terminals that are authorized to use wireless network 100, whether they are network subscribers or roamers or pre-paid users, etc. Each subscriber profile comprises information that is specific to the particular wireless terminal it is associated with, such as GPRS settings to allow packet services, settings to enable services requested by the subscriber, and location information (that was received from other entities) about the wireless telecommunications terminal, etc. Home location register 111 is well known in the art.
Service control function (“SCF”) entity 113 is an element of network 100 that is associated with providing supplemental services, such as CAMEL-based roaming or pre-paid calling. A service control point is an example of a service control function entity. The service control function entity implements the supplemental services desired by the operator, e.g., pre-paid accounting. In GSM networks, there is a CAMEL GSM entity known as the “gsmSCF” that performs the service control function, as is well known in the art. Service control function entity 113 and gateway mobile location center 109 are depicted here as two distinct elements of network 100 to emphasize their distinct functions and roles within the network.
General packet radio service (“GPRS”) support node (“GPRS support node”) 115 is analogous in some functions to mobile switching center 101, but differs from mobile switching center 101 in that it supports packet data services to the wireless terminals in contrast to the circuit switched service provided by mobile switching center 101. GPRS support node 115 is CAMEL-enabled, meaning that it (non-exclusively) communicates CAMEL-compliant signaling to and from other elements of wireless network 100 as described in more detail below. In some CAMEL-enabled networks, a CAMEL-enabled GPRS support node 115 also collects information that is needed for pre-paid call accounting and charging. GPRS support node 115 is well known in the art.
Wireless terminal 150 is illustratively a GSM cellular telephone. It will be clear to those skilled in the art that wireless terminal 150 can be another type of wireless terminal that is compatible with the serving wireless network, e.g., 3GPP, UMTS, TDMA, CDMA, etc. Wireless terminal 150 can be a cell phone, a smartphone, a data tablet, or a combination thereof. Wireless terminal 150 is well known in the art. When considering detection, surveillance, and tracking of wireless terminal 150, FIG. 2 is instructive.
FIG. 2 depicts an illustrative portion of a location-related signal flow among several legacy elements of wireless network 100, including wireless terminal 150, base station controller 103, serving mobile location center 107, mobile switching center 101, GPRS support node 115, service control function entity 113, gateway mobile location center 109, and home location register 111—as available in the prior art. FIG. 2 also depicts: per-subscriber operator input 200, signals 201 through 214, and status bubble 215. The illustrative signal flow occurs when a subscriber's identity is flagged for purposes of detecting, tracking, and surveilling the location of the subscriber's wireless terminal. It will be clear to those skilled in the art that this representation is a simplification of actual network signaling traffic, which is intended to improve understanding of the process and is not intended as an exhaustive tutorial.
Bubble 200 represents one or more operations by a network operator to input per-subscriber data into home location register 111. When a subscribing wireless terminal is “of interest” for purposes of surveillance/tracking/detection, the network operator updates the subscriber profile of the given wireless terminal to indicate that it is “of interest” as is well known in the art. Illustratively, the identity of interest is wireless terminal 150. Notably, bubble 200 represents a per-subscriber operation, based on whether the subscribing identity is “of interest” or not. When a subscribing identity is “of interest,” the updated subscriber profile indicates that a service control function in the network, e.g., service control function entity 113, is to be notified of the occurrence of one or more mobile-telecommunications events at wireless terminal 150, such as a call origination.
Signal 201 is from home location register 111 to mobile switching center 101 and GPRS support node 115. When wireless terminal 150 receives service from a given mobile switching center and/or GPRS support node, the wireless terminal is said to be “attached” to the respective serving mobile switching center and/or serving GPRS support node. The serving mobile switching center/GPRS support node, upon receiving signal 201, creates a local entry indicating that service control function entity 113 is to be notified when the serving mobile switching center/GPRS support node becomes aware of mobile-telecommunications events occurring at wireless terminal 150.
Signals 202 and 203 are from wireless terminal 150 via network infrastructure element(s) to mobile switching center 101 and/or GPRS support node 115, respectively. These signals notify mobile switching center/GPRS support node of mobile-telecommunications events experienced by the wireless terminal, such as a call origination, a location area update, a call ending, a packet data session origination, etc. Mobile switching center/GPRS support node consults its local data entry indicating that service control function entity 113 is to be notified.
Signal 204 is a CAMEL-compliant signal from mobile switching center/GPRS support node to service control function entity 113 that notifies service control function entity 113 of the mobile-telecommunications event at wireless terminal 150. Illustratively, signal 204 is a CAP signal.
Signal 205 is from service control function entity 113 to gateway mobile location center 109. Signal 205 requests the location of wireless telecommunications terminal 150 from gateway mobile location center 109. Illustratively, signal 205 is also a CAMEL-compliant CAP signal.
Signal 206 is from gateway mobile location center 109 to home location register 111. Signal 206 requests from home location register 111 the identity of the serving mobile switching center/GPRS support node for wireless terminal 150. This information is centrally kept by home location register 111 in wireless network 100.
Signal 207 is from home location register 111 to gateway mobile location center 109, responding with the identity of the serving mobile switching center/GPRS support node.
Signal 208 is from gateway mobile location center 109 to the serving mobile switching center/GPRS support node, e.g., mobile switching center 101 and/or GPRS support node 115, requesting a location for wireless terminal 150.
Signals 209, 210, 211, and 212 collectively represent the location-related signaling among wireless telecommunications terminal 150 and base station controller 103 and serving mobile location center 107 that ultimately provides to the requesting mobile switching center/GPRS support node an estimated location for wireless terminal (in signal 212). Depending on the implementation of the system, the location estimate could be provided by wireless terminal 150, serving mobile location center 107, or base station controller 103 as is well known in the art. As before, this is a simplified representation.
Signal 213 is from serving mobile switching center 101 and/or GPRS support node 115 to gateway mobile location center 109, reporting the estimated location for wireless terminal 150.
Signal 214 is from gateway mobile location center 109 to service control function entity 113, reporting the estimated location for wireless terminal 150.
Bubble 215 indicates that, at the conclusion of the illustrative signal flow, the location estimate for wireless terminal 150 is now available at service control function entity 113. The estimated location can now be used for surveillance or tracking purposes, for example.
As noted earlier, several disadvantages accrue to the prior-art mobile detection method according to the illustrative message flow of FIG. 2. For example:                The “of interest” identities are entered and updated in home location register 111 by the network operator. The fact that the network operator is involved in the surveillance process raises security concerns from the perspective of law enforcement authorities, and further raises privacy concerns from the perspective of those being tracked.        Every time a location request is invoked, a substantial amount of signaling traffic is required.        The home location register is not typically equipped to handle a large number of and/or frequent location detections, thus creating a bottleneck in the wireless network.A more streamlined approach to mobile detection and surveillance is therefore desirable.        